The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . pound permanenttiibe of vulcaniteor hard rubber and carrying at oneend a short electro-magnet, the coil ofwhich through itsterminals t, t is in- ^j_eluded in the cir- ^^ ^°- 7.—Bells hand telephone, present form. Il-il^^r^i instrument is in use. In front of the electromagnet,with Its plane normal to the axis of the magnet, is fixed a thin softiron disk about IJ inches in diamet
The Encyclopedia britannica; a dictionary of arts, sciences, and general literatureWith new maps, and original American articles by eminent writersWith American revisions and additions, bringing each volume up to date . pound permanenttiibe of vulcaniteor hard rubber and carrying at oneend a short electro-magnet, the coil ofwhich through itsterminals t, t is in- ^j_eluded in the cir- ^^ ^°- 7.—Bells hand telephone, present form. Il-il^^r^i instrument is in use. In front of the electromagnet,with Its plane normal to the axis of the magnet, is fixed a thin softiron disk about IJ inches in diameter, whic?^has its cover cu? to aconvenient shape to form a mouthpiece. This telephone acts wellk?,Lw f/^^tter or as a recefver; but for the former „etl ° A^^T V^^ ? «?, of tl^^ gr<=at advances which fiavebeen made in microphone has been stated that BeU and Elisha Gray almost simultane- ,.. Bellsliquidtrans-mitter. of instrument proposed bythe former and said tohave been exhibited at thePhiladelphia exhibition isshown in fig. 8. It con-sists of a speaking tubeor mouthpiece M, acrossthe lower end of which amembrane D is the centre of the mem-brane a light rod R, madeof metal or of carbon, isfixed with its length atright angles to the planeof the membrane. Underthe lower end of R a smallmetallic vessel C is sup-ported on a threaded rod,working in a nut fixed tothe sole F, so that its heigh t may be readily adjusted. ~8. Fie 9 Suppose C to be filled with 8 -Bell s liquid tnnsmitter water or any other con- Fio 9-Ehsha Gray s ... nd transmit terducting liquid, and the rod R to be of metal. C is raised until tholiquid just touches the point of the rod, when advantage is tnkenot the change of contact resistance with the greater or less immer-sion of R during the vibration of D. Good results were obtaineJwith mercury as the liquid and with a rod of carbon The
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Keywords: ., bookcentury1800, bookdecade1890, bookidencyclopedia, bookyear1892
